First thing I'd try is re-enabling live preview mode on the misc tab of the config app.
I'd also set the recordings and live tv directory to something sensible in the config app. Its trying to create a live tv file in the C:\ directory which isnt allowed in Vista.
Thank you so much!!! I'm now able to watch live tv. A seemingly obvious question, but I'm assuming that in order to watch hd channels, I'll need to add the astc capture source back?